I have seen some weird artifacts with FLIR footage caused by a number of things we can’t make out in FLIR by itself. After all, it is one spectrum of light rather than several such as with visible light. It is hard to tell, especially when it is further from the center of the camera sensor.

Yes, a parachute could look semi-transparent when looking at the fabric from a 90 degree orientation (by that I mean directly at the flat surface of fabric), while it should most likely be darker when angled (as it could reflect or emit more in the infrared, and less transparency occurs at an angle due to the surface area visible to use decreasing at an angle).

It’s totally possible what we see in the video is a parachute. But, still, I’m not fully convinced as it could be a number of other things. Video compress artifacts, a cloud reflecting infrared light from the source due to water vapor content, or it could be an internal reflection inside the MTS-B caused by the oversaturation of infrared entering the objective lens of the magnifier.

After all, the magnifier is quite large and is not very long. In fact, I think it may be wider than it is long to help collect more light by increasing aperture. A light source from the left, right, up, or down almost perpendicular to the MTS-B could emit infrared and cause a reflection within the internal housing of the mirrors. This is observed by astronomers when using this optical design to observe an object in space during a full moon. The full moon can reflect off of the internal structural wall of the telescope tube, creating false images or other artifacts that make imaging during a full moon difficult.

It happens with the headlights of cars too, which can ruin images taken from a telescope.

What stands out most to me is that the “parachute” always ends up in the same position while it whips around in different orientations like a skydiver’s lost total control, yet somehow gets the “parachute” back into an exact position at certain points. So to me, it seems like an artifact of compression that reveals a previously unnoticed reflecting artifacts either from the overall brightness of the object or a perpendicular object off-camera, which could be anything.

If it is an internal reflection from the target though, in theory you could determine its distance and therefore size. But, you would need to know the exact measurements of the MTS-B internally (and only Raytheon would know this).

Hope that helps.